Fix PyTket

[mpharrigan]

There's something fishy going on with the pytket notebook. When running in the doc build system it says

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-1-2f5bab2028d6> in <module>
     13     return pytket.device.Device({}, {}, arc)
     14 
---> 15 tk_circuit = pytket.cirq.cirq_to_tk(circuit)
     16 tk_device = _device_to_tket_device()

AttributeError: module 'pytket' has no attribute 'cirq'
AttributeError: module 'pytket' has no attribute 'cirq'

and when I try to execute it in colab it complains about a bad sympy version

ERROR: pytket 0.7.1.1 has requirement sympy~=1.6, but you'll have sympy 1.1.1 which is incompatible.

and when I run the import pytket part, the kernel dies with some information in the logs:

AttributeError: module 'sympy.core.core' has no attribute 'numbers'

[rmlarose]

Still failing on colab for me w/ same error:

ERROR: pytket 0.7.1.1 has requirement sympy~=1.6, but you'll have sympy 1.1.1 which is incompatible.

Can this be fixed?

https://colab.research.google.com/github/mpharrigan/recirq/blob/2021-02-pytket/docs/qaoa/routing_with_tket.ipynb#scrollTo=8cBvm5NrNCXt

[mpharrigan]

I know it says "ERROR" but does it actually prevent the notebook from working?

On colab, if I put pip install pytket~=0.7 pytket-cirq~=0.7 sympy~=1.6 it worked fine. I truly don't understand why the pip resolver doesn't upgrade sympy. Even in the error message it says "you'll have". I think it doesn't want to upgrade the system sympy installed in colab?

[rmlarose]

I know it says "ERROR" but does it actually prevent the notebook from working?

It ran until the cell importing pytket, at which point "Your session crashed for an unknown reason."

[rmlarose]

Latest commit pinning sympy~=1.6 runs through on colab.

[rmlarose]

I truly don't understand why the pip resolver doesn't upgrade sympy. Even in the error message it says "you'll have". I think it doesn't want to upgrade the system sympy installed in colab?

I think so, I'm also mesmerized by it though. I tried multiple combinations of pip install -q git+https://github.com/quantumlib/ReCirq with --ignore-installed, --upgrade, and --force-reinstall flags. I managed to upgrade sympy, but also a bunch of other packages got upgraded and caused more issues...

[mpharrigan]

Good to know. We'll go with this current fix for now!